stomach or other digestive organs acting on the external skin (which is
still in sympathy with the stomach and bowels,) and benumbing it, the
sensations sent up to the brain by double touch (that is, when my own
hand touches my side or breast,) are so faint as to be merely equivalent
to the sensation given by single touch, as when another person's hand
touches me. The mind, therefore, which at all times, with and without
our distinct consciousness, seeks for, and assumes, some outward cause
for every impression from without, and which in sleep, by aid of the
imaginative faculty, converts its judgments respecting the cause into a
personal image as being the cause,--the mind, I say, in this case,
deceived by past experience, attributes the painful sensation received
to a correspondent agent,--an assassin, for instance, stabbing at the
side, or a goblin sitting on the breast. Add too that the impressions of
the bed, curtains, room, &c. received by the eyes in the half-moments of
their opening, blend with, and give vividness and appropriate distance
to, the dream image which returns when they close again; and thus we
unite the actual perceptions, or their immediate reliques, with the
phantoms of the inward sense; and in this manner so confound the
half-waking, half-sleeping, reasoning power, that we actually do pass a
positive judgment on the reality of what we see and hear, though often
accompanied by doubt and self-questioning, which, as I have myself
experienced, will at times become strong enough, even before we awake,
to convince us that it is what it is--namely, the night-mair.

In ordinary dreams we do not judge the objects to be real;--we simply do
not determine that they are unreal. The sensations which they seem to
produce, are in truth the causes and occasions of the images; of which
there are two obvious proofs: first, that in dreams the strangest and
most sudden metamorphoses do not create any sensation of surprise: and
the second, that as to the most dreadful images, which during the dream